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Lake San Marcos, CA
Full City Profile · California · Orange County County
2.9
/5.0
C+
Fair
4,996
Population
2,922/sq mi density
$100,676
Median Income
$57,383 per capita
$859,600
Home Value
$943,389 Zillow
$2,615
Median Rent
32.1% income on rent
63°F
Avg Temperature
330 sunny days/yr
216
Violent Crime/100K
1,416 property/100K
C+
Overall
2.9 / 5.0
Fair overall score based on economy, affordability, safety and education
A+
Economy
5.0 / 5.0
$100,676 median income, 1.7% unemployment
D
Affordability
1.8 / 5.0
$859,600 home value, $2,615/mo rent
F
Safety
1.0 / 5.0
216 violent crimes/100K
B+
Education
3.8 / 5.0
35.5% bachelor's degree or higher
Lake San Marcos enjoys a temperate climate with an average annual temperature of 63°F (17°C). Winters average 56°F in January while summers reach 69°F in July. The area gets 330 sunny days per year. Annual precipitation totals 11.4 inches. Air quality is rated Good with a median AQI of 48.
Temperature
56°F Jan (14°C)
69°F Jul (21°C)
| Annual Average | 62.5°F |
| 16% above US avg | |
| January Average | 56°F (14°C) |
| July Average | 69°F (21°C) |
| Sunny Days | 330 days/yr |
Geography
| Elevation | 503 ft (153 m) |
| Area | 1.8 sq mi (4.7 km²) |
| Population Density | 2,922/sq mi |
| Coordinates | 33.1224°N, 117.2086°W |
| Timezone | America/Los_Angeles |
| County | Orange County County |
| Nearest Airport | San Diego International (SAN) 27 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 48.0 |
| Rating | Good |
Air Pollutants (EPA 2023)
| Ozone (O₃) | 0.0440 ppm |
| NO₂ (Nitrogen Dioxide) | 18.4 ppb |
| CO (Carbon Monoxide) | 0.35 ppm |
| PM2.5 (Fine Particles) | 9.7 μg/m³ |
Natural Hazard Risk
| Overall Risk | Very High |
| Risk Score | 99.8 / 100 |
| Social Vulnerability | 24.9 / 100 |
| Community Resilience | 16.3 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | No Rating |
| Earthquake | Very High |
| Wildfire | Relatively High |
| Flood | Very High |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively High |
| Winter Weather | Very Low |
| Lightning | Relatively Moderate |
| Drought | Relatively Low |
| Cold Wave | No Rating |
| Landslide | Relatively High |
| Coastal Flood | Relatively High |
| Tsunami | Relatively Low |
| Avalanche | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Tsunami History
2 tsunamis recorded within 500 km. Highest wave on record: 1.2 m (4 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1862 | S. CALIFORNIA | Eruption + Earthquake | 1.2 m | — | 47 km |
| 1855 | S. CALIFORNIA | Eruption + Earthquake | — | — | 137 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Nearby Volcanoes
1 volcano within 200 km. Closest: Salton Buttes (149 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Salton Buttes | Lava dome(s) | -40 m (-131 ft) | 210 | 149 km |
Source: Smithsonian Institution Global Volcanism Program (GVP). Sorted by distance.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 56°F (14°C) | 2.5 in | Wettest |
| February | 57°F (14°C) | 2.3 in | |
| March | 57°F (14°C) | 2.3 in | |
| April | 60°F (16°C) | 1.0 in | |
| May | 63°F (17°C) | 0.3 in | |
| June | 66°F (19°C) | 0.1 in | |
| July | 69°F (21°C) | 0.0 in | Driest |
| August | 72°F (22°C) | 0.1 in | Warmest |
| September | 70°F (21°C) | 0.3 in | |
| October | 66°F (19°C) | 0.4 in | |
| November | 60°F (16°C) | 1.6 in | |
| December | 56°F (13°C) | 1.8 in | Coldest |
Lake San Marcos has a seasonal temperature swing of 16°F / from 56°F in December to 72°F in August. Total annual precipitation is 12.7 inches, with January being the wettest month (2.5") and July the driest (0.0").